Most luggage is provided either with quick action slide fasteners when the luggage is flexible or with several locks spaced along the frame when the luggage is rigid.
Except on expensive luggage, locks do not properly withstand a prolonged use due to excessive strains to which they are subjected. Usually, there is a single central lock with two lateral folding hooks disposed on either side of, and equally spaced from, the central lock. However, these accessory fastening devices cannot be locked and if they yield because the luggage is over-filled, or for any other cause, the cover frame is liable to undergo a distortion so that the luggage gaps open.
Among known devices, those disclosed in the three patents summarized hereinafter may be cited.
German Pat. No. 1,902,360 to Schmale describes a closing device comprising a closing member (38) provided with lateral apertures (37) and an angle-bar (35) with closing hooks (36) provided with a shoulder and a bevelled face, but this device does not comprise a single and central opening and locking control system controlling the hasp assembly.
U.S. Pat. No. 1,455,069 to Launder describes a lock formed from a pair of tubes (1, 3) sliding in each other and responsive to a spring (9). Each one of the tubes comprises apertures (2, 12) adapted to receive closing hooks (8, 13). In such a lock, the risk of jamming two concentric tubes slidably fitted in each other is rather substantial and it is necessary to provide a relatively strong spring leading to a considerable opening pressure.
British Pat. No. 556,115 to Drescher and Kiefer relates to a lady's handbag clasp in which a finger (14) provided with an oblique surface (15) acts only upon the lock member, but its action must be conjugated with a tractive effort exerted on the lower edge (6) of the lock frame (1), hence the necessity of using both hands for opening the lock.